Hoists are used throughout manufacturing industries to lift assemblies or modules into place for installation. In particular, hoists are frequently used in aircraft manufacturing operations.
For example, crew rest areas are included in commercial passenger and long haul cargo aircraft, such as the Boeing 777LR. Some of these crew rest areas are designed to be included in the crown of the fuselage, that is directly over the center seats. In order to accommodate the crew rest areas, wiring and ducting are moved outboard of the crown. Composite crew rest modules containing seats and bunks are suspended between specially engineered rails that also support stowbins located above seats in the cabin, as shown in FIG. 1. Up to six modules, providing bunks and seats for up to twelve crew members, can be installed fore and aft in the fuselage crown.
In a current fabrication/installation method, the crew rest modules are built as complete assemblies. The complete assemblies are then lifted into the crown of the airplane and secured in place. By installing complete modules with this method, flow time in the factory is conserved. Due to the large size and heavy weight of these modules, crew rest module installation requires a specific type of mechanical lift to correctly locate the modules in the crown of the fuselage. Space restrictions, portability, range of motion, and airplane floor loading concerns preclude the use of commercially available scissors lifts.
Shape, weight, and size of the crew rest modules preclude personnel from physically lifting the modules. The largest module is 84 inches wide, 56 inches tall, up to 113 inches long, and weighs over 600 lbs. Modules are typically loaded into the airplane sections prior to joining sections of the airplane. While moving the modules into the airplane, care must be taken not to load the airplane floor beyond 250 psi. A typical commercially available scissors lift capable of raising a module to the required waterline, about 97 inches off the floor, would weigh 1500 lbs. or more plus the weight of the module. A load weighing nearly one-ton would have to be maneuvered in the plane and the weight distributed across the floor.
In addition, there is no known scissors lift configuration capable of handling the weight and reaching the required height that will collapse sufficiently while carrying a crew rest module to fit in the headroom available within the airplane fuselage
Therefore, there currently exists an unmet need to safely and efficiently raise crew rest modules or other modules into place at the crown of an aircraft fuselage.